1. Four particles are moving on a plane under the same constant acceleration \( \vec{a} = \hat{y} \), each having its initial velocity vector as follows: (a)\( 10\hat{x}+10\hat{y} \), (b)\( 10\hat{x}+8\hat{y} \), (c)\( 8\hat{x}+10\hat{y} \), (d)\( 12\hat{x}+12\hat{y} \). If the respective displacements are \( R_a \), \( R_b \), \( R_c \), \( R_d \), which of the following is correct?
(A)\( R_a ＞ R_b ＞ R_c ＞ R_d \)
(B)\( R_c ＞ R_b ＞ R_d ＞ R_a \)
(C)\( R_d ＞ R_a ＞ R_b ＞ R_c \)
(D)\( R_d ＞ R_a ＞ R_c ＞ R_b \)

(E)\( R_a ＞ R_c ＞ R_b ＞ R_d \)